Finder for motion-picture cameras and similar optical appliances



Feb. 19 1924.

O. D. TAUERN ET AL FINDER FOR MOTION PICTURE CAMERAS AND SIMILAR OPTICAL APPLIANCES If I /V@ /l //V& m 1 U 1 w I III!" I IIIOII! l H H m a 1 1 a I Q 5 H W 1 6 1 V 1 H U 7 1 f 1 I 1 I I I a H f; F A 3 H v 1 1 u 2 "v m a w .3 1 8 I 1 1 1 U n l A! llf l/ I I I, ////////vV y////////// 5 6 W M u, lrl 1 n I 1 z I 7 I 1 I a .1 2 I o Patented Feb. l9, 1924.

PATENT oFFlcE.

one 1). raunrm AND NIKOLAUS LYON, or rnmnuno, GERMANY.

FINDER FOB MOTION-PICTURE CAMERAS AND SIMILAR OPTICAL APPLIANCES.

Application filed August 1, 1922. Serial No. 579,075.

To all whom it may concern:

Be it known that we, 000 D. TAUERN and NIKOLAUS LYON, citizens of Germany, residents of Eggstrasse #5, Freiburg, Germany, have invented a useful Improvement in a Finder for Motion-Picture Cameras and Similar Optical Appliances, of which the following is a full, clear, and exact specification, reference being had therein to the accompanying drawing.

In cinematographs the practice of observing the picture by means of a screen picture is known, the latter being produced by a partial reflection of the rays by a glass 1| plate inserted diagonally in the ray path of the objective. This device which is very desirable for the purpose of continually supervising the icture as to its sharpness and contents, is or this reason hardly prac- 2 tical for motion picture cameras, as the picture produced on the finder screen is altogether too weak.

The invention consists in that the finder icture is not obtained on a screen, but by inserting directly behind the picture windows in the path of the finder rays a system of lenses which as a positive optical link produces a real picture of the object to be taken and which can be examined with a magnifying glass or similar 0 tical appliance, and despite the very sma l ray portion which 'is taken from the main picture, is exceedingly ra id. Furthermore, the false light falling t rough the ocular into the finder below is dispersed and weakened by the stem of lenses, so that no effects of this alse light are seen in the film. The drawing shows one application of a motion picture camera in simplified form, to wit; in horizontal longitudinal sections,

whereby- Figure 1 is a sectional view of a camera embodying one form of our invention.

Figure 2 isa' similar view showing a modified form of the invention. 4

Behind the objective tube 1 of the camera according to Fi re 1 a thin plane glass plate2 is inserte at an angle of 45 in such manner that it catches part of the icture rays in front of the film window 3, re ecting them laterally. A com letely reflecting prism 4 is arrangedlateral in the direction of the reflected rays in suc manner-that it turns aside these rays a second time, giving them a direction parallel to the objective axls.

The rays deflected by the prism 4 fall through the system of lenses 5 into a finder 6 of the description of a magnifying glass. A diaphragm 7 arranged between the diagonal plate 2 and the prism 4 limits the tentative picture in size and shape in the same way as the principal picture is limited in the film window 3.

The glass 2 is arranged to slide in a guide 8 in such manner that it can be taken out of the ray path of the objective 1, when not necessary fo'r'producing a finder picture.

In the second application according to Fig. 2 the'parts 1, 2, 3 and I remain unchanged as above described. In place of the lens system 5 a regular condenser lens system 5 is provided which is in front of the refracting prism 4 and immediately behind the finder window 7. In addition the finder is sub-divided into an objective 6 and an ocular 6 the latter of which may be shifted longitudinally. I

The condenser system 5 receives the entire picture limited by the finder window 7 and breaks the diverging rays in such manner that the entire picture falls into the finder objective 6* which, in turn, produces a real picture which may be examined through ocular 6".

Having now fully described and ascertained the nature of our invention and in what manner the sameis to be performed, we declare that what we claim is: y

In a motion picture camera, an objective, a plane glass plate placed diagonally behind the objective to cause part of the light to pass therethrough and deflect the remaining lesser part of the light rays laterally, a film window behind said glass plate and in line with the objective, a lens system in the path of the deflected rays behind the picture plane, a finder in which a real picture 'of the object to be taken is produced by said lens system and a screen corresponding to the size of the picture and arranged between said glass plate and said lens system and in the path of the deflected rays.

In witness whereof we afiix our signa- 1-0 ture's.

DR. ODO D.,TAUERN. DR. NIKOLAUS LYON. 

